Frederick w



mmm, ma. 1,597,759

' i F. .Wa BRAUN I Pnocss oF FUMIGATION Filed June 8, 1922 Patented ug.31, 1926.

starr'` rar:

raarste raras FREDERICK '\,V. BRAUN, OF LOS AUGELES, VC LLTFORNBA,ASSIGNOR lTO CALFB-NIA CYANIDE COMPANY, INCORPORATED, ACORPORATON OFDELAVF'ARE.

rnocnssy or Fuiirrenrron.

Appnauon alsdann@ s,

My linvention relates to the art of fumigation, and it is particularlyapplicable to the fumigation of orchards. It is common practicev infruit producing countriesv and particularly vin countries producingcitrus fruit to provide for the furnigation of the trees at statedintervals. This fuinigation is Ordinarily accomplished in citrusorchardsby enclosing the tree in a l0 portable cover, or tent, thus providing aspace in andaroundthe tree which is to `be filled with the fumigatingagent. The fumigating lagent is then introduced into this fumigatingspace and it'should be so'introduced that it 'penetra-tes into allportions of this space if itis to be efficacious. Tn such fumigation,various fumigating agents may be used, thezfumigating agent generallypreferred'in' the vcitrus countries being hydrocyanic acid, or someother lethal agent in the form of a gas or vapor. n The methodnoW ingeneral use of introducing hydrocyanic f acid into the fumigating spaceis to introduce it in the formo-f a spray, that is, in the form of aliquid ina highly atomized condition. .Wrhen hydrocyanic acidisvintroduced into a fumigating space in this manner, a certain amount ofvaporization of the hydrocyanic acid takes .50 place, but unless this.space lis at a suitable temperature and. unless the trees and otherobjects `Within the space are moderately Warm Ythe hydrocyanic` acidwill` condense upon the. surface of the tent, the limbs and foliage/ofthe trees'and upon the surface of the ground. l

- Since iny "the fumigation of orchards a definite dosage has been foundyto be efficient .and it is common practice for economical A reasons toVsupply to the fumigating space an exact dosage, it is evident thatthisuncer tain factor of condensation tends to prevent an efficient use ofthe vfumigating agent due to the uncertainty as to the amount of condueto the vaporization of the fumigating agent also tends to produce astratification of thefumigating vapors in the space to be fumigatedWitha furtherloss in efficiency.

It is an obj ect of my invention to' provide a process of and apparatusfor fumigating by the-use of hydrocyanic acid Vor a similar fumigatingagent Which will obviate the defects-ofthe present method justdescribed.

densation. This condensation'and coolingV This I accomplish byintroducing into thejV 1922. semi NQ. 566,838.

space to be fumigated the vapor of a substance hereinafter calledastabilizer Which has a higher boiling point than the fumigating agent,this vapor also preferablyv being introduced above its boiling point andabove the average temperature prevailingin the fumigating space.

Tn practice when hydrocyanic acid isused, l preferto use Water vapor asa. stabilizer, water not only having a higher boiling point thanhydrocyanic acid but also having a boiling point in excess of thetemperature found in and around the fruit trees which it is sought tofumigate. The Water vapor also has a high latent heat of vaporizationand is preferably introduced in intimate mixture with the vapor ofthe-fumigating agent. Upon contacting Withr the surfaces inside thefumigating space, the Water vapor tends'tocondense at temperaturesconsiderablyv above those at which the hydrocyanic acid tends tocondense, during its condensavtion givingup its latent heat ofvaporization Which tends to maintain the temperature inside the space tobe fumigated and thus to very materially retard the condensation of thefuinigating agent in this space. Since the Water Vvapor and thefumigating agent are intimately mixed, the latent heat of vapori'zationof the Water vapor is released at any point at which condensation wouldtend to talre place and thus prevents condensation of the vfumigatingagent at that point.

`While my process may be practiced With many forms of apparatus, f havedevised a special form Qfapparatus which is quite etlicient in 'carryingon the process, thisv form of apparatus being illustrated in the annexeddrawing in `which F ig. l is a diagrammatic elevation of an apparatussuited to carry on my process, and F Qvis an enlarged cross section ofthe measuring device.

The apparatus, as illustrated, consists of a gasoline or 'other fueltank l which is provided with a pressure gauge 2 and which supplies fuelto a gasoline burner 4L through a feed pipe having a valve 3. The burner4 is placed below a boiler 5 having 'a Water gauge 6 and a steampressure gauge 7. VThe boiler may also'be provided with a safety valve19 if desired. The boiler furnishes steam to a steam line 8 whichcommunicates With a steam valve 9 to Which'a compression chamber l0 isconnected. The compressionV chamber 10 is also connected into a standardgether so that they may be opened andl closed simultaneously by asuitable operating lever 80. The measuring device 14 is con.

structed as shown in Fig. 2, having Va piston 20 which may be adjustedup and down in a cylinder 21, the amount of this adjustment ybeingdetermined by a linger 22 engaging a rack 15. VA valve 23 which may beclosed by means of a hand wheel 24 is provided in the piston. The spaceabove the piston 2() in c the cylinder 21 is connected to a hydrocyanicacidcontainer 17 through piping 16. The mixture of steam and hydrocyanicacid are delivered from the injector 11 through a pipe 18 to the spaceto be fumigated.

The method of operation is as follows:

Steam being raised in the boiler 5 by the oil burner 4, the pressure ofthis steam may be read on the gauge 7 and maintained at any desiredpoint by a suitable manipulation of the fuel valve 3 or by any otherconvenient means. The valves 9 and 12 being closed, the valve 23 isopened and a definite dosey of hydrocyanicacid is allowed to flowthrough the pipe 16 and through the valve 23 into the lower part of themeasuring device 14, the amount of this dose being deter-` mined by theheight of the piston 20 which may be regulated for any desired dose bymeans of the rack 15. As soon as the space in the lower part of themeasuring device 14 is filled, the valve 23 is closed by means of thehand Wheel 24. The valves 9 and 12 are then opened, admitting steam intothe chamber 10 and simultaneously into the injector and drawing thehydrocyanic acid from the measuring device 14 through the pipe 13, thespring loaded valve 35 and the valve 12. The steam and hydrocyanic acidare intimately mixed in the injector, the miX- ture of steam andhydrocyanic acid being forced under pressure through the pipe 18 intothe space to be fumigated. As soon as the hydrocyanic acid is entirelyexhausted from the measuring device 14, valve 35 closes automaticallyand the valves 9 and 12 are closed. The compression chamber 10 containssteam and blows sufficient steam through the line 18 to clear it of anyhydrocyanic acid vapors which may be contained therein. By a suitableadjustment of the injector 11, the minimum proportion of steam tohydrocyanic acid canrbe quite accurately regulated. I have found that aconsiderable excess of steam is not injurious.`

By introducing steam or'vvater vapor into the fumigating space, Iprovide a carrier and stabilizer for the hydrocyanic acid and alsoprovide a source of heat `supply which tends to hold the hydrocyanicacid in vapor form and prevent premature condensation thereof. i

I claim as my invention:

1. 'A process of fumigating comprising: introducing into the space to befumigated a fumigating agent comprising hydrocyanic acid; and a vaporhaving a higher boiling point than said fumigating agent.

2. A` process of fumigatng comprising: introducing into the space to befumigated a fumigating agent comprising hydrocyanic acid, and a vaporhaving a higher boiling point than said fumigating agent, said vaporalso having a higher boiling point than the average temperature of saidspace.

A process of fumigating comprising:

introducing into the space to be fumigated a fuinigating agentcomprising hydrocyanic acid; and a vapor'having a high latent heat; ofvaporization, and a higher boiling point than said fumigating agent.

4. A process of fumigating comprising:

a fumigating agent comprising hydrocyanic acid; and a vapor having ahigh latent heat of vaperization, and a higher boiling point than saidfumigating agent, saidvapor also having a higher boiling point than theaverage temperature of said space.

5. A Vprocess of fumigating comprising:

introducing into the space to beifumigated

